Process for rendering wool material unshrinkable and nonfelting product made thereby



Patented Feb. 8, 1938 v UNITED STATES PATENT omen rnoon'ss FOB. nnn'nsnmo woon amp unsnnmxsnnn AND NONFELTING PRODUCT MADE 'rnnnnnr tingham, England No Drawing. Application June 27, 1936, Serial N0. 87,805. In Great Britain July 17', 1935 Claims.

This invention relates to the treatment of materials consisting wholly or, partly of wool and which'may be in the form of loose fibres or in a manufactured form such as yarn and fabric 5 and has for its object to reduce or substantially eliminate their usual tendency to felt when washed in aqueous liquors. H

In describing this .invention the term felt is to be understood to refer to that property of ordinary wool which causes the individual fibres to close upon each other in washing, or other treatment in an aqueous liquor in which the wool material is repeatedly squeezed and rubbed, so that the wool material becomes denser and sponsible for the shrinkage which wool yarns and fabrics suffer when washed. .-Structurally,

the raw wool fibre comprises a central portion or cortex, with a coating protecting the same, this coating being visible as discontinuousareas under the microscope and, being known as the epithelial scales. Edges of these scales project from the general surface and cause a type of interlocking during mechanical working or milling, which resultsin a felting as the fibres can- .not slide one on another. It has heretofore been proposed to avoid such felting effects by chlorination, but a chlorination sufilcient to prevent felting caused a. resulting change in these epiao thelial scales to such an extent that the fabric formed from such fibers has, suffered damage and is harsh to the feel, and the cortex is in part exposed so that wear is rapid and wetting easy. Furthermore. the chlorinating agents'often had as "the characteristic of rapid action but were not able to penetrate quickly throughout the mass of material treated-so that there was lack of uniformity both in respect to individual fibres and with respect to the fibres as a mass. I have discovered, and this discovery forms th basis of my present invention, that the tendency of wool to felt may be reduced by treating it with sulphui'yl chloride. After such treatment it is desirable to remove unchanged sulphuryl chloride and its decomposition products to an extent such that the wool will not deteriorate during subsequentstorage. In order to secure uniform treatment of the wool material I have foundit convenient to apply the sulphurylchlo- 50 ride in the forxnof its vapour or whilst dissolved more compact. ,This property of felting is re-.

or dispersed in liquid which is substantially inert to the sulphuryl chloride and to the wool under the conditions of its employment, preferably a volatile organic solvent for sulphuryl chloride. I

The conditions under which the wool must 5 be treated with sulphuryl chloride to reduce to any desired degree its tendency to felt may be varied widely. For example, the temperature of treatment may be varied from hot to cold, the wool may vary from wet to dry, and the duration of the treatment may be short or prolonged.

I have found generally that increase in the initial moisture content of the wool, increase in the temperature oif treatment, increase in the concentration or amount of sulphuryl chloride applied to the wool,. increase in the duration of the treatment all independently enhance the effect of sulphuryl chlqridei n reducing the tendency of wool to felt. For example, 100 lbs. kilos) of air-dry wool fabric may be made substantially non-felting by treating it for one hour at 20 C. with 50 gallons (227 litres) of white spirit (which for the particular example has a specific gravity of 0.81) containing 1 gallon (2% by volume) of sulphuryl chloride or by exposing it in the wet state for about 5 minutes at 40 C. to the vapour of sulphuryl chloride. In general I prefer to treat the wool in its normal air dry state with sulphuryl chloride at room temperature. that is 15 to 20 C., but when desirable-I find it easy by simple trials to establish I other conditions for achieving the same result.

In most cases, treatment of lbs. (45 kilos) of normal air dry wool for one hour at 15 to 20 C. with 50 gallons (227 litres) of a suitable solvent containing 1 gallon (2% by volume) of sulphuryl chloride almost entirely eliminates the tendency of wool to felt so that it is thereby made substantially 'unshrinkable.

As solvent it is possible to use any liquid which is substantially inert to sulphuryl chloride and which does not harm the wool, and it is preferable that it should be cheap and easily removed 45 from the wool after treatment by washing with water or voiatilizatlon. Among the solvents found satisfactory are white spirit (a petroleum fraction much usedin large- -scale dry cleaning and having a typical boiling point range from to, 50

' bon tetrachloride, ether, and trichlorethylene.

Whilst this, invention may be used to make wool substantially non-felting it is apparent that the conditions of treatment with sulphuryl chloride may be made less severe or otherwise modified so that the wool is left with any desired interthe mass of fibres and these treated fibres thus mediate (reduced) tendency to felt.

An advantage of the employment of a solution of sulphuryl chloride in white spirit or similar solvent is that such solution has high penetrating power and is thus able to penetrate rapidly and completely wool in package form, for example, tops of wool, and wool yarn in skeins, and wool yarn wound tightly in the form of cops.

Further, in applying sulphuryl chloride dissolved in an organic solvent to raw or oily wool, the solvent removes a large part of the fats and greasy impurities so that the wool may afterwards be are by way of illustration only, and do' not limit this invention in any way.

' hydroextracted fabric is then washed with'cold water, neutralized with a dilute aqueous solution of ammonia, washed with water, and dried.

Example 2.20 lbs. (9 kilos) loose raw wool is steeped for one hour at 18 C. in 10 gallons (45 litres) of white spirit containing 0.2 gallon (0.9,

litres) of sulphuryl chloride. The wool is then hydroextracted, washed with water, neutralized with a dilute aqueous solution of sodium carbonate, washed, and dried. Yarns and fabrics made from this wool are substantially unshrinkable.

Example 3.--Skeins of wool yarn are suspended Y within a chamber and the air then exhausted by means of a. vacuum pump. The vapour of sulphuryl chloride is then admitted and allowed toreact with the wool until a sample withdrawn is found to be substantially non-felting. The whole of the wool is then withdrawn, preferably after first blowing out the residual sulphuryl chloride vapour with a current of dry air, then washed, neutralized, washed and dried.

250 C. and specific gravity of 0.78 to 0.84), car-' means as are usually employed in wool carbonization processes.

In the procedures according to the examples set out herein the wool is rendered substantially non-felting, but there is no substantial damage to the epithelial scales and these remain distinct and substantially uniform throughoutconstitute a substantially uniform product, without substantial loss in softness, color or strength.

I have also found that wooltreated by this invention acquires a moderately increased aflinity for acid dyes.

In working this invention I have found that in treating 100 lbs; (45 kilos) the. loss of solvent is about 1% gallons (6.75 litres) and of sulphuryl chloride about half a gallon 2.25 litres), but it will be readily understood that these amounts are only approximate and will vary with the condi-' tions and apparatus used.

Instead of using sulphuryl chloride as such, its components sulphur dioxide and chlorine may also be used.

Example '5.---Wool fabric or yarn is exposed to a mixture of sulphur dioxide and chlorine. or successively to sulphur dioxide and chlorine in either order. Occluded gas may then be removed by a current of warm air. The fabric or yarn-is finally washed and dried.

I declare that what I claim is:- l. The process of rendering wool substantially non-felting, which consists in reacting all fibers percent by volume solution of sulphuryl chloride in an inert organic solvent thereof initially at room temperature.

2. The process of rendering air-dried wool sub-- stantially non-felting, which consists in immersi- Example 4.-20 lbs. (9 kilos) wool yarn in the form of cops with paper centres are steeped for one and one-quarter hours at 18 C. in 10 gallons (45 litres) of white spirit containing 0.2 gallon (0.9 litres) of sulphuryl chloride. Alternatively the same liquor is circulated through the cops in a machine suitable for this purpose. The cops are then hydroextracted, and dried in a current of warm air.

I have found that this inventioncan be conveniently worked in conjunction-with the carbonizing of wool. Thus, when raw wool containing burr impurities is steeped in a solution of sulphuryl chloride in white. spirit so as to make it non-felting, and is then hydroextracted and placed for about half an hour in a chamber at ing it in a solution of sulphuryl chloride in white spirit of a concentration of about two percent by volume initially at room temperature, and

withdrawing the same from the solution after' substantially one hour of immersion and prior to substantial change of its softness and prior to substantial damage to its epithelial scales.

3. The process of rendering wool substantially non-felting, which consists in immersing it in a solution of sulphuryl chloride in white spirit of a concentration of about two percent by volume, removing the wool therefrom prior to substantial change of its softness and prior to substantial damage to its epithelialscales, washing the treated wool, neutralizing with an aqueous solu-, tion of basic inorganic agent which forms watersoluble sulphate and chloride salts, and washing with water to remove water-soluble salts.

4."The process of rendering wool substantially non-felting and of eliminating vegetable cellulose matterstherefrom, which consists in reacting all fibres thereof with sulphuryl chloride, withdrawing the same from such reaction while the epithelial scales are substantiallyundamaged and substantially uniform throughout the mass of fibres, removing excess solution; heating the treated material to effect carbonization of cellulosic matter present, the effects of said contacting and heating yielding a product which solvent thereof initially at room temperature, and

mechanically working and removing the resulting disintegrated ceilulosic residue from the wool material.

5. A textile material containing wool'flbres whichare substantially uniform in 'characteristics, and are non-felting and have substantially unchanged the softness and color of the 1m, treated wool and 'ha've distinct and substantially 3 undamaged 'epltheliel scale: which remnin od- .herent to the cortex during working in an aque- 0118 both, said fibres hevin: been reacted upon by a limited concentration of eulphuryl chloride for a limited period of time equivalent to the treatment 01' air-dry wool for one hour in a bath of eulphuryl chloride in white spirit at a concentration of two percent by volume initially at room temperature.

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